1. Field of the Invention
The present invention relates to a process for treating chemically stabilized, adhesive activated polyester material and to polyester material which has been treated by the process. The present invention also relates to an improved finish composition by which treatment is achieved.
2. Description of the Prior Art
It is well known in the art to treat polyester material with various formulations in an attempt to improve the adhesion of the material to substances such as rubber. For example, in U.S Pat. No. 4,210,700, multifilament polyethylene terephthalate yarn is treated with a two-part fiber finish composition. The first part is applied to the yarn after it is spun and the second part is applied as an overfinish subsequent to drawing. The second part is an oil-in-water emulsion containing defined amounts of coconut oil, polyoxyethylene hydrogenated castor oil and phosphated polyoxyethylated tridecyl alcohol neutralized with potassium hydroxide.
In U.S. Pat. No. 4,054,634, multifilament polyethylene terephthalate yarn is also treated with a two part finish, one part of which is applied after spinning and one part of which is applied after drawing. The first part contains a defined polyoxyethylated-polyoxypropylated monoether whereas the second part contains the monoether in combination with a defined epoxy ether silane and a sufficient amount of a water soluble alkaline catalyst, such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium acetate, potassium acetate and organic amine compounds, to raise the pH to 8-10. Also see U.S. Pat. No. 4,348,517 wherein the same epoxy ether silane is combined with the triglycidyl ether of glycerol and a defined diglycidyl ether and is used as a fiber finish for polyester yarn.
U.S. Pat. No. 3,793,425 also describes a process for improving the adhesion of polyester material to rubber. In the process, undrawn polyester yarn is coated with a composition containing an epoxy resin which is preferably buffered with an alkaline agent, such as sodium carbonate, lithium carbonate, potassium carbonate or ammonium hydroxide. The use of epoxy resins with alkaline catalysts to improve the adhesion of polyester to rubber is further disclosed in U.S. Pat. Nos. 3,423,230 and 3,464,878.
To improve chemical stability, polyester material with lower carboxyl end groups is employed. However, when such polyester material is bonded to rubber, significant adhesion problems can occur. In an attempt to alleviate this problem, U.S. Pat. No. 3,940,544 describes the use of a finish for polyester yarn comprising a defined polyalkylene glycol and a defined triol which is preferably prepared by reacting tris(2-hydroxyethyl) isocyanurate with propylene oxide and/or ethylene oxide.
In U.S. Pat. No. 4,397,985, regular or low carboxyl polyester yarn is treated to improve rubber adhesion by using a finish or overfinish composition which includes gamma-glycidoxypropyltrimethoxysilane and a catalyst therefor selected from the group consisting of urea and a cobalt, stannous, iron, nickel, zinc, manganese or chromium salt of 2-ethylhexoic acid or lauric acid in a carrier which is miscible in water.
Regular or low carboxyl polyester yarn is also treated to improve rubber adhesion in published European patent application No. 0043410. In the disclosed process, the yarn is spun and drawn, the drawn yarn is exposed to ultraviolet radiation and the exposed drawn yarn is treated with a finish composition comprising water and a defined silane.